* [syzbot] possible deadlock in snd_mixer_oss_ioctl1
@ 2021-10-23 19:35 syzbot
2021-10-24 14:07 ` Pavel Skripkin
0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2021-10-23 19:35 UTC (permalink / raw)
To: alsa-devel, broonie, joe, lars, linux-kernel, perex,
syzkaller-bugs, tiwai, tiwai
Hello,
syzbot found the following issue on:
HEAD commit: cf6c9d12750c Add linux-next specific files for 20211022
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=15d3d4c4b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=e694204255ade3a3
dashboard link: https://syzkaller.appspot.com/bug?extid=ace149a75a9a0a399ac7
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17c0530cb00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1129c952b00000
The issue was bisected to:
commit 411cef6adfb38a5bb6bd9af3941b28198e7fb680
Author: Takashi Iwai <tiwai@suse.de>
Date: Wed Oct 20 16:48:46 2021 +0000
ALSA: mixer: oss: Fix racy access to slots
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=167f6454b00000
final oops: https://syzkaller.appspot.com/x/report.txt?x=157f6454b00000
console output: https://syzkaller.appspot.com/x/log.txt?x=117f6454b00000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ace149a75a9a0a399ac7@syzkaller.appspotmail.com
Fixes: 411cef6adfb3 ("ALSA: mixer: oss: Fix racy access to slots")
============================================
WARNING: possible recursive locking detected
5.15.0-rc6-next-20211022-syzkaller #0 Not tainted
--------------------------------------------
syz-executor206/6529 is trying to acquire lock:
ffff888021ff09c8 (&mixer->reg_mutex){+.+.}-{3:3}, at: snd_mixer_oss_set_volume sound/core/oss/mixer_oss.c:316 [inline]
ffff888021ff09c8 (&mixer->reg_mutex){+.+.}-{3:3}, at: snd_mixer_oss_ioctl1+0x630/0x19a0 sound/core/oss/mixer_oss.c:375
but task is already holding lock:
ffff888021ff09c8 (&mixer->reg_mutex){+.+.}-{3:3}, at: snd_mixer_oss_set_volume sound/core/oss/mixer_oss.c:300 [inline]
ffff888021ff09c8 (&mixer->reg_mutex){+.+.}-{3:3}, at: snd_mixer_oss_ioctl1+0x4b1/0x19a0 sound/core/oss/mixer_oss.c:375
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&mixer->reg_mutex);
lock(&mixer->reg_mutex);
*** DEADLOCK ***
May be due to missing lock nesting notation
1 lock held by syz-executor206/6529:
#0: ffff888021ff09c8 (&mixer->reg_mutex){+.+.}-{3:3}, at: snd_mixer_oss_set_volume sound/core/oss/mixer_oss.c:300 [inline]
#0: ffff888021ff09c8 (&mixer->reg_mutex){+.+.}-{3:3}, at: snd_mixer_oss_ioctl1+0x4b1/0x19a0 sound/core/oss/mixer_oss.c:375
stack backtrace:
CPU: 0 PID: 6529 Comm: syz-executor206 Not tainted 5.15.0-rc6-next-20211022-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_deadlock_bug kernel/locking/lockdep.c:2956 [inline]
check_deadlock kernel/locking/lockdep.c:2999 [inline]
validate_chain kernel/locking/lockdep.c:3788 [inline]
__lock_acquire.cold+0x149/0x3ab kernel/locking/lockdep.c:5027
lock_acquire kernel/locking/lockdep.c:5637 [inline]
lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5602
__mutex_lock_common kernel/locking/mutex.c:607 [inline]
__mutex_lock+0x12f/0x12f0 kernel/locking/mutex.c:740
snd_mixer_oss_set_volume sound/core/oss/mixer_oss.c:316 [inline]
snd_mixer_oss_ioctl1+0x630/0x19a0 sound/core/oss/mixer_oss.c:375
snd_mixer_oss_ioctl+0x40/0x50 sound/core/oss/mixer_oss.c:390
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f0c06979fe9
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffea97dd558 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0c06979fe9
RDX: 0000000020000080 RSI: 00000000c0044d00 RDI: 0000000000000003
RBP: 00007f0c0693dfd0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0c0693e060
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [syzbot] possible deadlock in snd_mixer_oss_ioctl1
2021-10-23 19:35 [syzbot] possible deadlock in snd_mixer_oss_ioctl1 syzbot
@ 2021-10-24 14:07 ` Pavel Skripkin
0 siblings, 0 replies; 2+ messages in thread
From: Pavel Skripkin @ 2021-10-24 14:07 UTC (permalink / raw)
To: syzbot, alsa-devel, broonie, joe, lars, linux-kernel, perex,
syzkaller-bugs, tiwai, tiwai
On 10/23/21 22:35, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: cf6c9d12750c Add linux-next specific files for 20211022
> git tree: linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=15d3d4c4b00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=e694204255ade3a3
> dashboard link: https://syzkaller.appspot.com/bug?extid=ace149a75a9a0a399ac7
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17c0530cb00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1129c952b00000
>
> The issue was bisected to:
>
> commit 411cef6adfb38a5bb6bd9af3941b28198e7fb680
> Author: Takashi Iwai <tiwai@suse.de>
> Date: Wed Oct 20 16:48:46 2021 +0000
>
> ALSA: mixer: oss: Fix racy access to slots
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=167f6454b00000
> final oops: https://syzkaller.appspot.com/x/report.txt?x=157f6454b00000
> console output: https://syzkaller.appspot.com/x/log.txt?x=117f6454b00000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+ace149a75a9a0a399ac7@syzkaller.appspotmail.com
> Fixes: 411cef6adfb3 ("ALSA: mixer: oss: Fix racy access to slots")
>
> ============================================
> WARNING: possible recursive locking detected
> 5.15.0-rc6-next-20211022-syzkaller #0 Not tainted
> --------------------------------------------
> syz-executor206/6529 is trying to acquire lock:
> ffff888021ff09c8 (&mixer->reg_mutex){+.+.}-{3:3}, at: snd_mixer_oss_set_volume sound/core/oss/mixer_oss.c:316 [inline]
> ffff888021ff09c8 (&mixer->reg_mutex){+.+.}-{3:3}, at: snd_mixer_oss_ioctl1+0x630/0x19a0 sound/core/oss/mixer_oss.c:375
>
> but task is already holding lock:
> ffff888021ff09c8 (&mixer->reg_mutex){+.+.}-{3:3}, at: snd_mixer_oss_set_volume sound/core/oss/mixer_oss.c:300 [inline]
> ffff888021ff09c8 (&mixer->reg_mutex){+.+.}-{3:3}, at: snd_mixer_oss_ioctl1+0x4b1/0x19a0 sound/core/oss/mixer_oss.c:375
>
> other info that might help us debug this:
> Possible unsafe locking scenario:
>
> CPU0
> ----
> lock(&mixer->reg_mutex);
> lock(&mixer->reg_mutex);
>
> *** DEADLOCK ***
>
> May be due to missing lock nesting notation
>
Looks like typo in previous ALSA patch. [1] should fix it
[1]
https://lore.kernel.org/alsa-devel/20211024140315.16704-1-paskripkin@gmail.com/T/#u
With regards,
Pavel Skripkin
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2021-10-24 14:07 UTC | newest]
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2021-10-23 19:35 [syzbot] possible deadlock in snd_mixer_oss_ioctl1 syzbot
2021-10-24 14:07 ` Pavel Skripkin
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